Finally I found some time, and I will describe how did I take my test unit apart. I will tell you what I done, and what I learned. I hope my English will be understandable enough

First I tried to use some solvents, but without results.
Then I tried to heat it up in the oven: 75°C... 100°C... 125°C... Above 100 deg. back, black cover starts to be plastic, but the transparent front is not. This is very good news. The front is visible after all. I tried to lever up the front, but it wasn't moving. Only back part start to unbend. I could bend it back nearly to the same shape (80-90%).
Finally I decided to use full power and do everything I could. I choose one bottom corner of the unit and used a screw driver. After few tries the screw driver was inside! From accessed corner I had access to whole bottom rim. I used long screw driver to drill-in into it. There was some rim damage (unbending) but I didn't care. That part of the unit is not visible at all. I have some idea how to avoid it, but about it later...
When bottom rim was released I drill-in into side rims. It was the easiest part. Nearly no damage.
When I had 3 of 4 rims done, I thought I would be able to open the unit like a door, but no way! This glue is hard as a rock! Because of the shape of the unit, I couldn't drill in. I didn't want to damage that rim. It is visible with bonnet open.
Then I used method which I should use from the beginning: using two screw drivers (big and wide) levering up the two covers inch by inch. It was easy go and without damage. I made it after heating the unit, but I'm not sure if it is necessary.
The headlight is open!

Now. It wasn't the best method to do this. I would NOT do this again in the same way. Nothing is broken, but the bottom edge of back part is unbend in many places. Few pictures:

Now, if I had to dis-assemble next unit, I would do it in much different way:
1. Use mini drill or soldering iron to cut off bottom outside edge of the back coverhttp://img853.imageshack.us/img853/5778/159ad.jpg
2. Use knife/scalpel to cut off the glue from that rim
3. Use small screw driver to lever up bottom edge
4. Use two big and wide screw drivers to lever up front cover inch by inch
4a. If the glue is not ripping off easy enough - heat the unit up in the oven in 75-100°C for about 5 minutes (repeat after cool down)

When the unit taken apart in this way is stuck back together, the bottom cut-off edge can be just flood with the new glue. Headlight will be lake-proof again.

One more clue:
When you will clean up the back cover edge from the glue, cover the reflectors/mirrors with some sheet of paper to avoid dirt it with tiny glue pieces.
And as far as I know - TOUCHING THE INSIDE MIRROR PARTS IS FORBIDDEN as it can cause the mirror layer to come off in some time! Please correct me if I'm wrong.

I replaced some glued/sealed lenses many years ago on a vauxal omega and I had exactly the same problem with getting the glue to soften enough, I found the oven baking helped but was awkward handeling the unit with oven gloves and prying away.

What I ended up doing was using a soldering iron with a craft knife attatchment so it was like a "hot knife through butter"on the sealing glue, but still requires patients!:-)

If they prove to not effect the normal functionality and performance of the lights, and if someone makes them for me, I'd buy some... surely if we get enough people interesting in purchasing, it would be worth someone's while to produce them for sale?

IMO they just look tacky and a little chavvy, maybe that's just my previous experience with them?

The 159/Brera front end is gorgeous as it is, please don't go decorating it with fairy lights just because it's Christmas

Don, everyone is entitled to an opinion, and I thank you for yours. That said, peoples taste is individual, and although you don't like them, others do.

This is an experiment into the possible, therefore its probable it will never make it onto the actual car. Feel free to watch with glee and take your personal pleasure from the experience, and if you think you can add value, then please do.

Don, everyone is entitled to an opinion, and I thank you for yours. That said, peoples taste is individual, and although you don't like them, others do.

This is an experiment into the possible, therefore its probable it will never make it onto the actual car. Feel free to watch with glee and take your personal pleasure from the experience, and if you think you can add value, then please do.

Oh ye i'm not saying don't bother with it, it'll be interesting to see

I just hate seeing Saxo's/Golf's/Corsa's with the aftermarket angel eyes as they look poo IMO and wouldn't want people to ruin a gorgeous Alfa front end

Had a few thoughts that essentially needed writing down as they were keeping me awake!

1) The headlights are going to be a mare to get apart.
2) See above
3) Given points 1 & 2, its something I only ever want to do once.

So....

If I fit a CCFL inside and it blows, Its a problem. Same with LED rings. The idea of a bumper off, headlight out, oven bake procedure to change a broken halo is not appealing.

Plan B....

Although the guy who "made his own" LED rings from that earlier post clearly watched way too much blue peter and was on the crack pipe when he attempted the electronics, he was onto something. If, I manufactured a plastic ring that fits inside the reflector housing but extended into the rear of the light unit, then I would be able to glue the headlights back together forever, as I could project light from the rear of the unit and any LEDs that failed would be accessible through the normal way from the back. Also, it means I can use RGB LEDs to make the Halos change colour to orange in time with the indicators if I can find some high powered RGB ones that is!

The thinking is why not fit something directly in front of the headlight beam (bulb) that obscures the light with a control signal (electronic shutter) , but is small enough to allow a halo effect.
Then I though there must exist such a device and yes it's called electronic controlled privacy glass.

Had a few thoughts that essentially needed writing down as they were keeping me awake!

1) The headlights are going to be a mare to get apart.
2) See above
3) Given points 1 & 2, its something I only ever want to do once.

So....

If I fit a CCFL inside and it blows, Its a problem. Same with LED rings. The idea of a bumper off, headlight out, oven bake procedure to change a broken halo is not appealing.

Plan B....

Although the guy who "made his own" LED rings from that earlier post clearly watched way too much blue peter and was on the crack pipe when he attempted the electronics, he was onto something. If, I manufactured a plastic ring that fits inside the reflector housing but extended into the rear of the light unit, then I would be able to glue the headlights back together forever, as I could project light from the rear of the unit and any LEDs that failed would be accessible through the normal way from the back. Also, it means I can use RGB LEDs to make the Halos change colour to orange in time with the indicators if I can find some high powered RGB ones that is!

@Jay
I have the same worries.
Maybe any further re-installing of the rings will be not the same hard, as we can use a different glue. E.g. that same sticky, but reacting with some solvent.
Removing the bumper will be easier each next time as well.
Next - remember that SMD are very long life. I think if any ring will fail after 5 years it will be surprising quick.

If you are still not convinced, I have one more idea for you
If you will look at single lampshade cross section you will find (from outside):
-removable outside silver cover
-transparent front cover
-internal silver reflector

My plan X is to cut off the middle section of each lampshade, inch or two behind front lid. It need to be done very precisely! No burrs!
Then all modifications can be made with easy access. When done, glue the lid back to the unit with some silicon glue. To ensure that lid will be not rotated, make some marker first.
When whole headlight will be assembled back together, there will be no sign at all!
Schema: http://img341.imageshack.us/img341/8714/159lw.jpg

Huge pros:
-if any ring will broke, you will be able to... fix it on the car! You will just remove the front cover, use a knife to cut off your glue, remove the lid, clean the edges, replace the ring and.... and only sticking it back together w/o nice access from the bottom can be tricky. But doable.

As you can see from the schema, there is one more pros:
-in our previous plan, if you will use wrong glue, or do it wrong - the whole front cover can come off When you will do the same mistake in new plan, the silver external cover's shape will keep it in place.

I just spent most of the morning trying to get the unit apart and have literally given up after over cooking it in the oven!! As the lenses are actually thin plastic and not glass I can confirm that their tolerance to heat is not as much as the glue, also the glue is far more tolerable to heat than the entire headlight in general, so oven baking to split this unit in production is not a viable option. (I now have a slightly droopy looking even more battered headlight than I started )

I think the idea of cutting the lenses is ok and had been considering that myself, but I have another cunning plan. I have a friend that can vaccume form plastic, and I am going to see if we can make a mould from the chrome covers that look the same, but are made of perspex. By doing this we can chrome the units as per the originals but leave a halo style front edge to the unit exposing the perspex. Then applying a high powered led to the hidden top edge at the back would light the front ring.

This mod would not require any access to the internal parts of the light nor would it require any cutting. essentially, it would be a plastic replacement kit for the existing parts. You would still need to drop the bumper an inch or two to get to the screws on the bottom of the facier plate of the headlights, but that would be it.

No need for dozens of LEDs just 3 x high power RGB ones. I have found some 3 x 1 Watt per channel RGB LEDs that are surface mount so only 2mm think and about 1cm square. one of these positioned behind each of teh 3 plastic surrounds will generate more than enough light

You are right though, although in principle a good idea, the manufacturing process is not going to be straightforward and is beyond my DIY ability so I am seeking some advice from a friend on the subject.

If anyone on this thread has a plastics background and could help, please chirp in!!

Don't forget if you are going to drive these high power LED's hard they will get hot and need a heat sink, as their life will be considerably cut short.

yup, on it. the overall design will account for heat distribution for the LEDs, voltage regulators, micro-controller and other ancillaries. Also, I am not planning on driving the LEDs at full power constantly which will reduce heat and extend life. bear in mind, to get white out of one of these you use all 3x1 watt channels so that's a 3w LED, which is one hell of a lot of light! across each light unit that would be 9w which is about the same as a 40w halogen bulb, so they are going to be rained back for use, but may have full power, tied to a flash.

All still theoretical at this stage until I can get some advice on the surrounds.

Guys, the site that was linked to in the original post (Image Car) and seems to be the inspiration for this thread is a Ukranian website making halo kits for all sorts of cars. Apparently, modifying cars is huge in the Ukraine.
As luck would have it I have a work colleague that is Ukranian. Not only that but they are going back for Christmas. Not only that but they are also from Kiev (where the Image Car guys are from) and will be literally 5 minutes round the corner from them visiting the in-laws!
I asked her to translate their website and see what she could discover but she said it would be easier to call in there and talk to them directly and see if she can get her hands on a kit for me. She will bring it back as hand luggage if she can get one and also find out about getting more and shipping to the UK for me.